The conventional image-forming process of silver halide photography includes imagewise exposure of a photographic silver halide recording material to actinic radiation (such as actinic light), and the eventual manifestation of a useable image by wet photochemical processing of that exposed material. A fundamental step of photochemical processing is the treatment of the material with one or more developing agents to reduce silver halide to silver metal. With black-and-white photographic materials, the metallic silver usually comprises the image. With color photographic materials, the useful image consists of one or more images in organic dyes produced from an oxidized developing agent formed wherever silver halide is reduced to metallic silver.
To obtain useful color images, it is usually necessary to remove all of the silver from the photographic element after color development. This is sometimes known as "desilvering". Removal of silver is generally accomplished by oxidizing the metallic silver, and then dissolving it and undeveloped silver halide with a "solvent" or fixing agent in what is known as a fixing step. Oxidation is achieved with an oxidizing agent, commonly known as a bleaching agent.
Fixing is typically carried out using a fixing composition that includes one or more fixing agents such as thiosulfate salts. Both ammonium and sodium thiosulfate salts are known. Fixing solutions containing ammonium ions are preferred for providing more rapid fixing, but they present environmental concerns. Thus, fixing solutions containing sodium ions, while slower, are also advantageous.
Color photographic silver halide materials often contain various sensitizing dyes that extend the inherent photosensitivity of the photosensitive silver halide emulsions to electromagnetic radiation. One important class of such sensitizing dyes are carbocyanine sensitizing dyes that are commonly included in silver halide emulsion layers in photographic silver halide films, for example in color reversal photographic silver halide films (films normally used to provide positive color images).
Many photographic silver halide elements contain residual sensitizing dyes after photoprocessing. In some cases, the level of retained sensitizing dyes is inconsequential and thus, unobservable. In other instances, however, the high level of retained sensitizing dye results in undesirably high dye stain (or unwanted color) in the elements.
The problems with residual sensitizing dyes have also been satisfactorily addressed by incorporating certain stain reducing agents into one or more working strength photographic processing compositions. These compounds are described in copending and commonly assigned U.S. Ser. No. 09/464,551 filed Dec. 16, 1999 by Goswami et al and U.S. Ser. No. 09/464,961 filed Dec. 16, 1999 by Goswami et al as colorless or slightly yellow compounds having an extended planar .pi. system that is devoid of a diaminostilbene fragment or fused triazole nuclei. While these compounds can be incorporated into various photoprocessing compositions, it is preferred to include them in concentrated photographic fixing compositions.
However, when attempts were made to incorporate some of these stain reducing agents into concentrated processing solutions such as concentrated aqueous photographic fixing solutions, it found that several of them did not pass rigorous solubility tests. For example, many of them showed unacceptable solubility even when organic solvents were added, insolubility in solution at low temperature for lengthy times, or insolubility in concentrated fixing composition.
WO 97/10887 (Lowe et al) describes affinity ligands useful in the purification of proteins. These compounds include hundreds of possible ligands that may include 2,6-dinaphthylaminotriazines. This reference also describes some methods for making such ligands.
There remains a need for solubilized 2,6-dinaphthylaminotriazines that can be incorporated into concentrated photographic processing compositions that meet all manufacturing, customer use, and storage stability requirements.